rate-limiter.ts•2.78 kB
import { RateLimiter } from './types.js';
export class TokenBucketRateLimiter implements RateLimiter {
private tokens: number;
private lastRefill: number;
private readonly maxTokens: number;
private readonly refillRate: number; // tokens per millisecond
private readonly refillInterval: number; // milliseconds
constructor(maxRequests: number, windowMs: number) {
this.maxTokens = maxRequests;
this.tokens = maxRequests;
this.lastRefill = Date.now();
this.refillInterval = windowMs;
this.refillRate = maxRequests / windowMs;
}
private refillTokens(): void {
const now = Date.now();
const timePassed = now - this.lastRefill;
const newTokens = timePassed * this.refillRate;
this.tokens = Math.min(this.maxTokens, this.tokens + newTokens);
this.lastRefill = now;
}
canMakeRequest(): boolean {
this.refillTokens();
if (this.tokens >= 1) {
this.tokens -= 1;
return true;
}
return false;
}
async waitForAvailableToken(): Promise<void> {
return new Promise(resolve => {
const check = () => {
if (this.canMakeRequest()) {
resolve();
} else {
// Calculate time until next token is available
const tokensNeeded = 1 - this.tokens;
const msToWait = (tokensNeeded / this.refillRate) * 1000;
setTimeout(check, Math.min(msToWait, 100)); // Check at most every 100ms
}
};
check();
});
}
}
// Create rate limiters based on Trello's limits
export const createTrelloRateLimiters = () => {
const apiKeyLimiter = new TokenBucketRateLimiter(300, 10000); // 300 requests per 10 seconds
const tokenLimiter = new TokenBucketRateLimiter(100, 10000); // 100 requests per 10 seconds
return {
apiKeyLimiter,
tokenLimiter,
/**
* Checks if a request can be made without hitting rate limits.
* This is useful for pre-checking before attempting a request,
* allowing for more graceful handling of rate limits without blocking.
*
* @returns {boolean} True if both API key and token limiters have available tokens
*/
canMakeRequest(): boolean {
return apiKeyLimiter.canMakeRequest() && tokenLimiter.canMakeRequest();
},
/**
* Waits until tokens are available for both API key and token limiters.
* This method blocks execution until rate limits allow the request to proceed.
* Used by the axios interceptor to ensure all requests respect Trello's rate limits.
*
* @returns {Promise<void>} Resolves when tokens are available
*/
async waitForAvailableToken(): Promise<void> {
await Promise.all([
apiKeyLimiter.waitForAvailableToken(),
tokenLimiter.waitForAvailableToken(),
]);
},
};
};